In 2014, Energy supply was the largest source of net
emissions (13.8
MtCO
2e), followed by Transport (including
International Aviation and Shipping) (12.9
MtCO
2e) and Agriculture and Related Land Use
(10.7
MtCO
2e).

Emissions from Business and Industrial Processes and the
Residential sector were the next largest net emissions sources
(8.7
MtCO
2e and 5.9
MtCO
2e respectively).

The combined total of emissions from the other net sources
(Waste Management, Development and Public Sector Buildings) was
less than 5
MtCO
2e.

Forestry was the only aggregate sector in which there has
been a net emissions sink (-10.2
MtCO
2e).

Carbon dioxide was the main greenhouse gas emitted or removed in
most sectors, with the exceptions of the Agriculture and Related
Land Use and Waste Management sectors.

Methane was the main net gas emitted in the Agriculture and
Related Land Use sector (4.7
MtCO
2e), followed by carbon dioxide (3.2
MtCO
2e) and nitrous oxide (2.7
MtCO
2e).

Almost all emissions in the Waste Management sector were
emitted in the form of methane (2.2
MtCO
2e)

Where F gases are emitted, they have been in relatively small
amounts via the Business and Industrial Process source sector, as
well as in the Residential sector.

Key Trends By Scottish Government Source
Sector

Chart B2 presents the main sources of Scottish Greenhouse Gas
Emissions in Scotland from 1990 to 2014, broken down by Scottish
Government source sector. Note that for the purposes of
presentation, some sectors have been grouped together on this
chart. Chart B3 and Chart B4 specifically explore the trend in
Energy Supply emissions. Chart B5 contains information on the
absolute and percentage reductions in greenhouse gas emissions in
every Scottish Government source sector over the entire time
period, with Chart B6 containing the same information for the
latest year.

Most sectors exhibit a general downward trend between 1990 and
2014, most clearly evident since 1998.

In all years, energy supply is the main source of greenhouse
gas emissions, although it has a seen a sharp fall in 2013 and
2014. This is partly linked to the closure and mothballing of
power stations and means that energy supply emissions in 2014 are
now 0.9
MtCO
2e higher than emissions from transport
(including international aviation and shipping). The chart shows
that energy supply is a very volatile sector. This is driven by
the fact that energy demand is linked to the ambient temperature,
particularly during the winter months; and fuel used for
electricity production, which in turn is partly driven by the
price of coal relative to "cleaner" fuels. Charts B3 and B4
demonstrate these effects in more detail.

Much of the fall in emissions from the Business and
Industrial Process sector occurred between 1990 and 1995. This
has been driven by a decline in emissions from manufacturing and
the iron and steel industry over this time period.

Net emissions from the agriculture and related land use
sector have seen a gradual decline between 1998 and 2014, which
can be linked to the impact of historic changes in land use,
change to cropland and grassland and also a decline in cattle and
sheep numbers.

Emissions from transport (including international aviation
and shipping) have seen a small overall reduction between 1990
and 2014. Emissions in this sector rose to a peak in 2007, before
falling slightly. The recent falls in emissions reflects a number
of factor including changes in emissions from cars stemming from
improvements in car energy efficiency. Road transport emissions
have been affected by changes in the make-up of the passenger car
fleet. In recent years, there has been an increase in more fuel
efficient diesel engines compared with petrol vehicles.

Residential emissions have shown a downward trend between
1990 and 2014, although they have fluctuated substantially in
recent years and are partly generated by heating of homes.
Residential emissions in 2014 were the lowest in the series, due
to the warmer external temperatures in that year.

Waste management emissions have fallen between 1998 and 2014.
This is due to the progressive introduction of landfill gas being
captured and used for energy. There could also be other factors
which are contributing to this reduction such as improvements in
the standards of landfill sites and changes to the types of waste
going to landfill.

The size of the net carbon sink from forestry increased
between 1990 to 1999, before remaining broadly constant in more
recent years. Between 1990 and 2014, there has been an increase
in the area of forest land. However, the rate at which land is
being converted to forestry from other land uses has decreased
over time. This is partly because the rate of afforestation has
decreased over the last 40 years. In addition, conifer
plantations, which were established in the mid-20th century, have
reached their planned rotation age and are now being felled and
replanted - leading to a fairly constant level of carbon
sequestration since 1999, albeit with a slight reduction in the
sink in recent years.

Chart B3 shows that the generation of Scotland's electricity
changes over time. Emissions from the electricity supply sector
(such as power stations) are associated with these changes.

Chart B3. Generation of Electricity by Fuel,
Scotland, 2004 to 2014. Percentage of Electricity Generated by
Year

The share of Scottish electricity generation arising from the
renewables sector (including hydro natural flow) has increased
from 11.7 per cent in 2004 to 38.0 per cent in 2014.

There was a sharp drop in the proportion of electricity
generation coming from gas between 2013 and 2014 (from 10.3 per
cent to 5.4 per cent). This is likely to be the result of a gas
fired power station being mothballing in 2014. This latest drop
continues the decline in the share of electricity generation from
gas from 2008 onwards, when it was 23.2 per cent.

The proportion of electricity generation coming from coal has
changed little between 2013 and 2014. However, the amount of
electricity generated from coal has fallen between 2013 and 2014.
This is likely to be because of the closure of a coal fired power
station in the early months of 2013. Overall, there has been a
fall in the proportion of electricity generated from coal since
2006, although this series is volatile, with 29.5 per cent of
Scottish electricity supply being fuelled by coal in 2010.

A third of Scotland's electricity supply came from nuclear
energy in 2014. This represents an increase from 2007, when
nuclear energy represented 25.7 per cent of Scotland's
electricity supply.

Chart B4 shows the gas and coal prices for large users in the
UK. The use of coal
rather than gas in electricity generation can be sourced to these
price effects in many cases. In 2014, the relative price of coal
per kilowatt hour was slightly less than half that of gas, although
it was higher than in 2013.

Chart B4. Gas and Coal Prices for Large
Users in the
UK (2004 to 2014) - pence
per kWh

Long term (1990 to 2014) and short term (2013 to 2014)
trends by sector

Chart B5 shows how emissions have changed between 1990 and 2014
in all source sectors. Chart B6 shows how emissions have changed
between 2013 and 2014.

Chart B5. Change in Net Emissions by
Scottish Government Sector Between 1990 and 2014 - in
MtCO
2e,
and percentage changes[5]

Chart B6. Change in Net Emissions by
Scottish Government Sector between 2013 and 2014 - in
MtCO
2e,
and percentage changes[6]

Total Emissions

Overall, there has been a 30.5
MtCO
2e (39.5 per cent) decrease in net emissions
between 1990 and 2014 and there has been a 4.4
MtCO
2e (8.6 per cent) decrease in net emissions
between 2013 and 2014.

Energy Supply

This sector has seen an 8.9
MtCO
2e (39.2 per cent) fall in emissions between
1990 and 2014 - the largest absolute fall of any sector. Charts B2
to B4 shows that this series is very volatile. This is largely
driven by changes in the fuel mix for electricity production. The
Energy Supply sector also saw the largest absolute decrease of any
sector between 2013 and 2014 - a 2.1
MtCO
2e (13.4 per cent) decrease.

The largest contributor to the reduction in energy supply
emissions between 2013 and 2014 has been power stations. In
particular, a gas fired power station was mothballed in May 2014. A
coal fired power station was also closed in March 2013 with some
remaining emissions being reported for 2013, but not in 2014. There
have also been falls in emissions from combustion in refineries and
from gas production between 2013 and 2014.

Residential

This sector has seen a 2.1
MtCO
2e (26.0 per cent) fall in emissions between
1990 and 2014. Between 2013 and 2014, there was a 1.2
MtCO
2e (16.4 per cent) fall in residential
emissions - the largest percentage reduction of any source sector
in the latest year. Residential emissions are partly generated by
space-heating homes and thus are related to external temperatures.
The mean annual temperature in 2014 in Scotland was the highest in
a series going back to 1910. It was 0.93°C higher than in 2013
and 0.98°C higher than the 1981-2010 average
[7]. Chart B7 shows that the first 6 months of 2014 were
considerably warmer than in the equivalent period in 2013 and the
1981-2010 average. As a result of this relationship to external
temperatures, residential emissions can exhibit some large annual
fluctuations.

This sector has seen a 7.6
MtCO
2e (77.3 per cent) fall in emissions between
1990 and 2014 - the largest percentage fall of any sector over this
time period. This is due to the progressive introduction of
landfill gas being captured and used for energy and due to the
reduction in biodegradable municipal waste going to landfill. There
could also be other factors which contribute to this reduction,
such as improvements in the standards of landfill and changes to
the types of waste going to landfill. Between 2013 and 2014, the
Waste Management sector saw a fall of 0.3
MtCO
2e (12.8 per cent).

Business and Industrial Process

This sector has seen a 5.7
MtCO
2e (39.6 per cent) fall in emissions between
1990 and 2014. As shown in Chart B2, much of this decrease occurred
between 1990 and 1995 - linked to a decline in emissions from
manufacturing and the iron and steel industry over this time
period. There has been a further smaller decrease between 2008 and
2009, coinciding with the recession. Figures have then been more
level in recent years, albeit with small fluctuations in emissions
from this sector since 2009. There was another decrease (0.5
MtCO
2e; 5.9 per cent) in emissions in this sector
between 2013 and 2014. This has been driven a number of factors,
which include a reduction in emissions from combustion in the
petrochemicals industry, and from the space heating of offices,
which is partly linked to external temperatures. There was also a
smaller drop in emissions from pulp and paper making.

Agriculture and Related Land Use

This sector has seen a 3.6
MtCO
2e (25.0 per cent) fall in net emissions
between 1990 and 2014. This has been driven by a fall in emissions
of carbon dioxide (Chart B9), methane (Chart B10) and nitrous oxide
(Chart B11).

The fall in carbon dioxide emissions from the agriculture and
related land use sector has partly been due to the effects of
historic land use changes. For instance, there have been changes in
the area of land being converted from other uses to cropland.
Between 1990 to 2014, the rate at which land has been converted to
cropland has fallen, with more land now remaining as cropland and
not being changed to other uses. The process of land being
converted to cropland releases carbon dioxide. Over time, this
process gradually emits less carbon dioxide. There has also been an
increase in the net sequestration of carbon dioxide from
grassland.

Methane emissions from agriculture have fallen from 1990 to 2014
due to a decline in cattle and sheep numbers - with a corresponding
fall in emissions from enteric fermentation and animal wastes.
Nitrous oxide emissions have also fallen over this time period,
albeit with a slight increase in recent years. The overall decrease
in emissions between 1990 and 2014 could be due to improvements in
practices on agricultural soils and a decline in livestock
numbers.

Between 2013 and 2014, there was a 0.2
MtCO
2e (1.7 per cent) decrease in net emissions of
overall greenhouse gases from this sector. This is due to a
continued reduction in emissions from land being converted to
cropland and an increase in the net greenhouse gas sink from
grasslands. There has been a very slight (around 1 per cent)
increase in emissions from agricultural soils in the latest year -
despite a general downward trend over time. This could be due to
increased use of nitrogenous fertilisers.

Forestry

This sector has seen a 1.4
MtCO
2e (16.1 per cent) increase in its carbon sink
between 1990 and 2014. The majority of the sink arises from the
large area of conifer plantations in Scotland, which is subject to
forest management such as thinning and harvesting. The increase in
the carbon sink is due to an increase in the area of forest land
over this time period. The area of land being converted to forest
from other land uses has been decreasing over time, with more land
remaining as forestry.

Carbon sequestration from forestry increased between 1990 and
1999. However, over the last 40 years the rate of afforestation has
decreased and with conifer plantations established in the mid-20th
century reaching their planned rotation age now being felled and
replanted. This has resulted in the size of the annual sink
remaining relatively constant from 1999 onwards, albeit with a
slight reduction in sequestration in recent years. Between 2013 and
2014, there was a small reduction (0.1
MtCO
2e) in the size of the carbon sink from
forestry.

Transport (Including International Aviation and
Shipping)

Between 1990 and 2014, emissions from transport (including
international aviation and shipping) fell slightly. Chart B2 shows
that emissions rose to a peak in 2007, before falling slightly.
This slight fall has been largely caused by changes in road
transport emissions. As well as reflecting improvements in car
energy efficiency, road transport emissions have been affected by
changes in the make-up of the passenger car fleet, with an increase
in more fuel efficient diesel engines compared with petrol
vehicles. Up to 2007, there was a large increase in car vehicle
kilometres travelled. There was a slight drop in car vehicle
kilometres travelled in the years after 2007, but this value has
increased by 2014 to around 2007 levels.

Breaking transport emissions down further, between 1990 and
2014, there was a 0.8 per cent decrease in transport emissions
(excluding international aviation and shipping) and a 10.9 per cent
decrease in emissions from international aviation and shipping.
International aviation emissions have more than doubled between
1990 and 2014 (from 0.5
MtCO
2e to 1.2
MtCO
2e). This reflects the growth in aviation and
the increase in international routes at airports. Emissions from
international shipping have fallen by 46.8 per cent between 1990
and 2014 (from 2.0
MtCO
2e to 1.1
MtCO
2e). This is primarily due to a decrease in
Scotland's port freight movements.

Between 2013 and 2014, there was a 0.5 per cent increase in
emissions from transport (excluding international aviation and
shipping). There has been an increase in emissions from light good
vehicles (0.06
MtCO
2e; 4.1 per cent) between 2013 and 2014. There
has also been a slight increase in emissions from cars between 2013
and 2014 (0.04
MtCO
2e; 0.7 per cent), which is linked to an
increase in car vehicle kilometres.

Between 2013 and 2014, there was a 5.5 per cent increase in
emissions from international aviation and a 10.2 per cent decrease
in international shipping. It should be noted that the data series
for international shipping is particularly volatile.

Public Sector Buildings

This sector contributes a small proportion of Scotland's net
greenhouse gas emissions. The main source of emissions from this
sector is the use of natural gas for heating public buildings.
There was a 0.6
MtCO
2e (36.2 per cent) fall in emissions from
public sector buildings between 1990 and 2014. This has been
largely driven by a reduction in the use of oil and coal for space
heating. Between 2013 and 2014, there has been a 0.2
MtCO
2e (14.2 per cent) fall in emissions from this
sector, and this has been partly linked to less space heating for
buildings because of the warmer external temperatures in 2014.

Development Emissions

This sector captures net emissions from settlements and from
land converted to settlements. It accounts for only a small
proportion of Scotland's net greenhouse gas emissions. There was a
0.3
MtCO
2e (13.8 per cent) decrease in development
emissions between 1990 and 2014. Between 2013 and 2014, there was
very little change in emissions from this sector.

Emissions by type of gas

Chart B8 shows the trends in emissions, broken down by gas from
1990 to 2014.

Carbon dioxide is by far the largest contributor of Scottish
greenhouse gas emissions in all years (73.7 per cent of all
emissions in 2014) and is the most volatile series of all gases -
largely driven by changes in energy supply emissions and to a
lesser extent, emissions from the residential and business and
industrial process sectors.

Methane in the second most common greenhouse gas in 2014
(16.1 per cent of all net emissions) followed by nitrous oxide
(7.0 per cent) and F-gases making up the remainder (3.2 per
cent).

Methane has seen the largest percentage reduction from 1990
to 2014 (57.5 per cent), which have been largely driven by a
reduction in waste management emissions. There have also been
percentage reductions for both carbon dioxide (37.6 per cent) and
nitrous oxide (21.3 per cent). Emissions from fluorinated gases
have shown a 7-fold increase from 1990 to 2014 and this increase
is driven by the introduction of hydrofluourocarbons (
HFCs) from 1995
onwards. These
HFCs replace
chlorofluorocarbons (
CFCs) which were
banned by the Montreal Protocol due to their impact on the ozone
layer.

Charts B9 to B12 present results on individual gases broken down
by main Scottish Government sectors over time. Table B3 contains
figures on all greenhouse gas emissions across the time series.
Chart B9 shows how carbon dioxide emissions have changed from 1990
to 2014.

Chart B9 shows that energy supply is the key source of carbon
dioxide emissions in all years between 1990 and 2014. Transport
(including international aviation and shipping) is the next most
common source of carbon dioxide emissions in all years apart from
1990, and is only 0.5
MtCO
2e lower than energy supply emissions in
2014.

Much of the decrease in carbon dioxide emissions between 1990
and 2014 has been driven by falls in the energy supply sector
across the time period and in business and industrial processes
between 1990 and 1995. Carbon dioxide emissions from the energy
supply sector have been quite volatile, with the highest
emissions occurring between 1995 and 2003, and a spike in 2006,
related to a greater use of coal in that year.

The agriculture and related land use sector has also seen a
fall in net emissions of carbon dioxide - largely due to changes
in land uses

Forestry has been a net sink of carbon dioxide consistently
between 1990 and 2014.

Methane emissions from waste management have fallen from 9.7
MtCO
2e in 1990 to 2.2
MtCO
2e in 2014 (a 77.9 per cent reduction). This
is due to the progressive introduction of landfill gas being
captured and used for energy. There could also be other factors
which contribute to this reduction, such as improvements in the
standards of landfill and changes to the types of waste going to
landfill.

Methane emissions in the agriculture and related land use
sector have fallen from 5.6
MtCO
2e in 1990 to 4.7
MtCO
2e in 2014 - a 15.3 per cent fall over this
time period. This reduction is partly linked to a fall in
livestock numbers.

In the Energy Supply sector, methane emissions have fallen
from 2.0
MtCO
2e in 1990 to 0.5
MtCO
2e in 2014, largely due to reductions in
emissions from sources such as coal mining.

The Agriculture and related land use sector is by far the
main contributor to emissions of nitrous oxide. These are largely
produced by agricultural practices on soils, and to a lesser
extent by animal manures. Emissions of nitrous oxide in this
sector have fallen from 3.2
MtCO
2e in 1990 to 2.7
MtCO
2e in 2014. This has been due to
improvements in practices in agricultural soils and a decline in
livestock numbers. There has been a very slight (around 1 per
cent) increase in emissions from agricultural soils in 2014. This
could be due to an increased use of nitrogenous fertilisers.

Emissions of nitrous oxide in the business and industrial
process sector have fallen from 0.5
MtCO
2e in 1990 to 0.1
MtCO
2e in 2014.

F gases are the most potent greenhouse gases with high global
warming potentials but they are emitted in very small quantities.
As a result, they contribute less to global warming than the
other greenhouse gases in Scotland.

There has been a sharp increase in F gas emissions from
business and industrial processes between 1990 and 2014 (from 0.2
MtCO
2e in 1990 to 1.3
MtCO
2e in 2014). This is because F gases were
introduced to replace chlorofluorocarbons (
CFCs), which were
used in appliances such as industrial air conditioning units.
CFCs were banned
under the Montreal Protocol, as they were contributing to the
depletion of the ozone layer.

F gas emissions in the residential sector are caused by the
use of aerosols and asthma inhalers, and represent between 0.15
and 0.20
MtCO
2e in the years between 1998 and 2014.